How to Manage Pests

UC Pest Management Guidelines

Sugarbeet

Wireworms

Scientific names: Agriotes spp. and Limonius spp.

(Reviewed 11/05, updated 1/10)

In this Guideline:

DESCRIPTION OF THE PESTS

Wireworms are beetle larvae that are found in soil where they feed on roots. They are yellowish brown, thin worms that have a shiny, tough skin. Adults of the wireworms are click beetles, so named because their elongated bodies are capable of producing a clicking sound. Only the larval stage causes damage.

DAMAGE

Wireworms feed on roots of emerging plants, killing the seedlings and reducing the stand. As plants mature, wireworms may girdle the stem. Be sure to dig around the plant and look for wireworm larvae to confirm that they are the cause of injury.

MANAGEMENT

Cultural Control

In fields known to contain wireworm larvae, fallow during summer with frequent tillage (springtooth or disk). Damage from wireworm infestations to the crop when it is in the seedling stage can sometimes be reduced by replanting. Rotate to nonhost crops if possible; contact your county farm advisor for information regarding nonhosts. Do not plant a susceptible host crop following a crop that has had a heavy infestation of wireworm without fallowing,tilling, or applying a pesticide.

Monitoring and Treatment Decisions

Wireworm infestations are difficult to detect before visible plant injury occurs. They are most likely to be found in a sugarbeet field when sugarbeet follows a long-term legume crop or natural or temporary pasture.

Chemical controls are ineffective or impossible to apply to wireworms attacking a standing crop. If used, chemicals must be applied as preplant or seed treatments.

Common name		Amount/Acre	R.E.I.+	P.H.I.+
(trade name)			(hours)	(days)
The following materials are listed in the order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees as well as the environmental impact. Not all registered pesticides are listed. Always read the label of the product being used.
A.	CHLORPYRIFOS
	(Lorsban) 15G	8 oz/1000 row ft	24	30
	MODE OF ACTION GROUP NUMBER1: 1B
	COMMENTS: Offers suppression only. Apply in-furrow at planting time. T-band or band at planting or postemergence.
+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
1	Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For more information, see www.irac-online.org.

PUBLICATION

UC IPM Pest Management Guidelines: Sugarbeet
UC ANR Publication 3469

Insects and Mites

E.T. Natwick, UC Cooperative Extension Imperial County
Acknowledgement for contributions to Insects and Mites:
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
D. R. Haviland, UC IPM Program, Kern County
L. D. Godfrey, Entomology, UC Davis

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